Boiler.



"' Patented Oct. 30, 1911' 5 SHEETS-SHEET l.

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APPLICATION FILED APR. 3. I917. 1,245,005. Patented Oct. 30,1917.

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uucmou FILVEO APR. 3. 1911. patenm Oct-.30, 1917.

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I? a I Edward C/Veier: I

Patented obn 30,1917:

Q 5 SHEETS-SHEET 5 BOILER APPLICATION man mm. 1911.

EDWARD C. MEIER, OF PHOENIXVILLE, PENNSYLVANIA.

BOILER.

Specification 01' Letters Patent.

Patented Oct. 30, 191 '7.

Application filed Apr113, 1917. Serial No. 159,399.

To all whom it may concern:

lie it known that I,.Enwnrm C. MEIER, a citizen of the United States,residing at lhoenixville, in the county of Chester and State ofPennsylvania, have invented certain new and useful Improvements in Boil-01's, of which the following is a. specification.

My invention consists of improvements in boilers, and more particularlyconsists of an improved construction and arrangement of super-heaterwithin a boiler.

One object of my invention is to form a superheater chamber and to solocate said chamber within a boiler that an extremely high degree ofsuperheated steam can be obtains Another object is to provide means forregulating the amount of the products of combustion passing into thechamber and thereby regulate the degree of the superheated steam.

Another object is to so design the means which form my improvedsuperheating chamber that it will be of simple construction and can beeasily and quickly installed in boilers of various types.

A further object is to so design my improved superheater constructionthat its use within a boiler serves to add to the efiicienoy of theboiler.

These objects, and other advantageous, ends which will be describedhereinafter, I attain in the following manner, reference be ing had tothe accompanying drawings in which Figure 1 is a sectional elevation ofmy improved boiler illustrating my improved super-heater constructionFigs. 2 and 3 are sectional elevations showing modifications of myimproved boiler and super-heater construction.

Figs. l'and 5 are sectional elevations of two well known types ofboilers having my improved superheater construction illus trated inconnection therewith.

Fig. 6 is a fragmentary sectional elevation showing a modification ofthe construction shown in Fig. 4 including a bafile formed of tile andresting upon the lower tubes 112 of the boiler unit 113.

Referring to Fig. 1, 1 represents the boiler casing having verticalfront, rear, and side walls, the rear wall 2 having an oil-set orstepped portion 3 which connects with the upper vertical portion 1 ofsaid rear wall, the off-set portion being substantially horizontal andforming an indentation 5 in the rear wall. An outlet passage for theproducts of combustion, is illustrated at 6, and a damper 7 is providedto regulate the amount of opening through said outlet passage, it beingnoted that a flue (not illustrated) can connect with said outlet passageand fit within the space provided by the indentation 5.

Two boiler units 8 and 9 are arranged within the casing 1, the boilerunit 8 comprising a plurality of water tubes 10 con necting at their topand bottom with drums 11 and 12. The boiler unit 9 and bottom with drums1 1 and 15. v

The drums 11 and 14 are connected by tubes 16, and the drums 12 and 13.are connected by tubes 17, it being noted thatjihe tops of the drums 1].and 14 are also connected by a tube 18 which acts-as an equalizing tubebetween the steam spaces of the drums 11 and 14.

The drum 14 has a main steam pipe 53 leading therefrom, and the drums l2and 15 have blow-off pipes 20 and 21 connecting therewith. The drums 11,12, 14, and 15, are arranged horizontally and supported within the sidewalls, the drum 12 being further supported by a pedestal 22 on thebottom oi the casing.

The drums l1 and 12 are in different vertical planes so that the tubes10 extend at an incline toward the front wall 23 of the casing. This isalso true of the drums 14 and 15 so that the tubes 13 also extend at anincline and substantially parallel with the, tubes 10 of the boiler unit8.

A grate 2st is provided adjacent the front wall 23 and at the bottom ofthe casing, thus producing a fire box 25 which is located forward of theboiler unit 8. A bafile 26 is provided between the tubes 10 and extendsupwardly from the drum 12 throughout a portion of the length of saidlatter tubes, stopping short of the drum 11 so as to provide a passage27 between it and. the drum 11. a

A baflle 28, extending between the oppositely disposed side walls of thecasing 1, is

includes a plurality of tubes 13 which connect at their top locatedbetween the tubes of the boiler units 8 and 9. This baffle is arrangedas illustrated substantially on a level with the top of the baffle 26and consists of fire bricks 29 which rest on angle bars 30. These anglebars are connected with a plate 31 and form a rigid supporting structurefor the bricks 29. Furthermore, the bricks bein located above andforward of the angle ars and plate, receive the direct heat of theproducts of combustion after passing through the passage 27 as will behereinafter more fully described, and thus protect said angles and plateagainst the direct heat of the products of combustion which passdownwardly to the rear of the baflie 26. I

A second baflie 32 is located between the boiler units 8 and 9 and is ofthe same construction as above described in connection with the baffle28, only that it is arranged at a lower level.

Another bafiie 33 is arranged between the tubes 13 of the boiler unit 9and extends downwardly from the drum 14. This baliie is supported at itslower end by an angle bar 34, this angle bar restin upon clamps 35, thelatter being adjustably secured to I the tubes 13 of the boiler unit 9.,

The lower end of the baffle 33 stops short of the drum 15, and thusprovides a passage 36 between it and said drum. The top of the bafile 32is arranged as illustratedsubstantially on the level with the bottom ofthe baflie 33.

I preferably form cleaning doors 35 and 36 in the side walls of thecasing and arrange these doors above the bafiles 28 and 32, so that anydirt collecting on the latter can be removed therefrom by a rakeinserted through said doors.

A comparatively small drum 37 is located on thetop of the boiler casing1 and has a feed water inlet valve 38 connecting therewith. The drum 37is connected to another small drum 39 bystraight pipes 40, said pipesextending through the casing 1 and into theinterior thereof to the rearof the tubes. 13 of the boiler unit 9.

The drums 37 and 39 have openings 41 and 42 respectively, which are indirect alinement with the straight pipes 40. These openings 41 and 42are closed by plugs 43 and 44 during the operation of the boiler.

Short p'pes 45 connect the drum 39 with the drum 15.

It will be noted that the drum 39 is partially embedded within the rearwall 2 of the casing and the o ening 42 and plug 44' are located outside0 said rear wall. This arrangement of the drums 37 and 39, and the pipes'40, permits the ready cleaning through the openings 41 and 42 from theoutside ofia-the boiler casing.

Within the chamber 1, I form an arch wall 46. This arch wall ispreferably made the forward tubes 10 of the boiler unit 8 at a positionsufliciently below the drum 11 so as to provide an outlet passage 48 forthe superheater chamber 49 which 1s formed by the baffle wall, archwall, and front and top portions of the casing 1.

Within the chamber 49, I insert a superheater 50 which, as illustrated,includes depending tubes 51 which intersect a header 52 located on thetop of the boiler, said header being connected by a steam pipe 53 whichleads from the drum 14, it being noted that the steam passes outwardlyfrom the drum 14 through the steam pipe 53, then through the head 52 andtubes 51 of the header, and eventually out through a pipe 54 whichconnects with the outlet end of the superheater.

The arch wall 46 has a passage 55 which communicates with thesuperheater chamber 49 and the fire box 25, it being noted that thepassage 25 is directly above the grate 24 so that the products ofcombustion can pass directly upwardly from the grate throu h the passage55 into the chamber 49. i y this construction, the superheater 50 can beheated to an extremely high temperature.

In order to regulate the amount of opening of the passage 55 into thecombustion chamber 49, I provide a damper 56 which rests and is designedto slide upon the upper surface 57 of the arch wall 46 between thebafiiei wall 47 and the front wall of the-casmg passage 45 by means of arod 58, said rod extending through the front wall of the easingl and atits outer end being provided ,with a'handle 59 so that a forward move--ment of the handle will tend to slide-the damper 56 from the positionshown in Fig. 1 to a positionwhich is directly over said passage. If itis desired to only partially close said passage, the rod 58 maybe'pulled until the damper is moved to such position as to give saiddesired amount of opening.

It will be noted that the outlet assage 48 from the superheater chamber49 is in alinement with the passage 27 formed between the upper end ofthe baflie 26 and the bottom The damper 56 can be slid over the of thedrum 11. Furthermore, it will be noted that by extending the arch wall46 into close proximity with the forward tubes 10 of the boiler unit 8,the portion of the products of combustion which do not pass through thepassage 55, -will be forced to pass through a passage 60 formed betweenthe inner end 61 of the arch wall 46 and the forward face of the bafile26, thus causing latter mentioned portion of the products of combustionwhich pass between the end 61 of the bafile wall 46 and the forward faceof the baflie 26, will also pass outwardly through the passage 62 intothe passage 27 and that portion of the products of combustion which passupwardly through the superheater chamber 49, will pass outwardly Kthrough the passage 48 and combine with said other portion of theproducts 'of combustion as they pass through the passage 27. Theproducts of combustion passing it through the passage 27 heat the drums11 and 14, upper portions of the tubes 10, and the upper portions of thetubes 13 which are forward of the baffle 33. These products then passdownwardly between the bafiles 26 and 33 and in so doing are split up ordivided by the bafiles 28 and 32, caus ing them to passbetween the reartubes of the boiler unit 8 and the forward tubes of the boiler unit 9. Aportion of said products of combustion then pass between the battles 26and 32 and serve to heat the drum 12, then move rearwardly and combinewith that portion of the products passing between, the baffle 32 and thebaflie 33. Then all of" said products of combustion combine andpass-through the passage 36 and upwardly to the rear of the bafiie 33and finally pass out through the outlet passage .6 to the flue.

In the form of my invention shown in Fig. 2, I have provided a casing 63in,which are mounted two water tube boiler units 64 and 65. The boilerunit 64 includes tubes 66 which connect at their top and bottom withdrums'67 and 68 respectively. In like manner, the boiler unit has tubes69 which connect at their top and bottom with drums 70'and 71respectively. The drums 67 and 70 are connected by tubes 72 and thedrums 68 and 71 are connected by tubes 73.

An equalizing tube 74 connects the drums 67 and 70 adjacent their top. Afeed water inlet valve 75 connects with a drum 76 within-the casing, andthis drum is connected to the drum 71 by a pipe 77. An

outlet passage 78 is formed within the casing to permit the products ofcombustion 7 8 so that its opening may be varied according to the draftdesired.

A baffle 80 is positioned between the tubes of the boiler unit 64 andextends upwardly from the drum 68 to a position below the drum 67,thereby providing a passage 81 between the top of the battle and thedrum 67. An arched baffle 82 extends from the rear tubes of the boilerunit 64 to the forward tubes of the boiler unit 65 and in a position insubstantial alinement with the top of the baffle 80.

A pedestal 83 is mounted below the drum 68, and a grate 84 extendsbetween this pedestal and the front wall of'the casing 63, thusproducing a fire box 85 directly above the grate 84. An arch wall 86 isformed within the casing directly above the grate 84 and fire box 85,this arch Wall 86 extending from the front wall of the casin 63rearwardly to the forward tubes 66 o the boiler unit 64.

A baflle wal.l87--connects with the inner end of the arch wall 86 andextends upwardly adjacent the forward tube 66 of the boiler unit 64.This bafiie wall 87 is of such height as to provide an outlet passage 88between its top and the bottom of the drum '67. Furthermore, the bafllewall 87, arch wall 86, and front and top portions of the casing 63,provide a superheater chamber 89 into which extends a superheater 90including tubes 91 which connect with headers 92 and 93, the header 93being in communicationwith the drum 70 through the medium of a steampipe 94, while the header 92 has an outlet pipe 95 for conveying thesuperheated steam for the purpose desired.

The arch wall 86 has a passage 96 which is directly above the 'grate 84and fire box 85 and communicates with the superheater chamber 89 in amanner similar to that described in connection with the passage. asshown in Fig. 1.

A damper 97 is designed-tn slide u the upper surface of the arch 11Lsaid damper 97 being movable by a, rod. eons nected thereto andextending l y the casing 63. The outer end of the- 98 is provided with ahandle'99 for convenience in moving the damper 97 backwardly andforwardly over the passage 96. It will thus be noted that the amount ofopening of the passage-96 into the superheater chamber 99 can be variedbv moving the rod'98 longitudinally, thus the amount of the products ofcombustion which pass into the combustion chamber 89 can be varied bythe movement of said damper. I

It will be noted that by the arrangement of the bafiie wall 87. directlyadjacent the forward tubes of the boiler unit 64, a passage 100 will beformed so that the portion of the products of combustion which do not130 pass through the passage 96 will. be forced to' pass through thepassage 100 and thereby closely hug and efliciently heat the tubes ofsaid boiler unit 64 which are located forward of the bailie 80.

That portion of the products of combustion which pass into thesuperheater chamber 89 will pass upwardly and outwardly through thepassage 88, where it will combine with the por ion of said productswhich pass upwardly through the passage 100. T hen the entire productsof combustion will pass through the passage 81.

Another baffle 101 is located between the tubes of the boiler unit 65and extends from the drum 71 upwardly to the drum 70. Therefore, theproducts of combustion after passing through the assage 81, willbe'divided, part passing own between the rear tubes of the boiler unit64 and the tubes which are forward of the bafile 101. Then all of saidproducts again combine and pass between the tubes 73, around the drum71, and upwardly to therear of the baflie 101 and eventually out throughthe passage 78, thus heating the tubes of the boiler unit which are tothe rear of the bafile 101 and the feed water.

In Fig. 3, I have shown a boiler of the same general construction asthat described iiiconnection with Fig. 2 with the exception that thecasing 102 'hasits outlet opening 103 adjacent the bottom of the rearwall instead of at the to as illustrated in Fig. 2, the design of saicasing being slig tly ehanged at the rear end.

The other difference of construction between Figs. 2 and 3, is that inFig. 3 in stead of the arched baffle shown in Fig. 2,

I have shown a bafiie wall 104. This baffle wall extends between the twoboiler units and at its top intersects the drum 70, since it will benoted that I have given similar parts corresponding reference numeralsin Figs. 2 and 3.

The lower end of the baffle wall 104 intersects the pedestal 83 and thedrum 71, and has a passage 105 adjacent its bottom which permits theproducts of combustion passing downwardly between the baflle 80 and thebaflle wall 104 to pass upwardly between the bafile 104 and the baflie106 it being noted that the baflle 106 is shorter than the baflle 101above described in connection with Fig. 2. A passage 107 is thusprovided between the top of the baflle 106 and the drum 70, so that theproducts of combustion after passing upwardly between the baffle wall104 and the baffle 106, will pass through the passage 107 and downwardlybetween the rear face of the baffle 106 and the rear wall of the casing102 and eventually will pass out of the outlet 103 to the flue.

In all other respects the constructions shown in Figs. 2 and 3 aresubstantially identical including the means which proride thesuperhcater chamber.

In Fig. 4. I have shown my superheater construction built in a boilerwhich. is known as the liadcnhausen boiler. In this construction, I haveshown an arch wall 108 which is built directly over the grate 109 andfire box 110. This arch wall extends from the front wall 111 of theboiler casing rearwardly into intersection with the tubes 112 of theboiler unit 113.

A bafile wall 114 extends upwardly adjacent the forward tubes 112 andstops short of the drum 115 to provide a passage 116 between the upperend of the bafile wall 114 and said drum 115, it being noted that theb-afiie wall 114, arch wall 108, and front wall of the casing 111provide the super-heating chamber 117 into which extends the superhcatcr118, said superheater communicating with the steam drum 119 through themedium of a steam pipe 120.

The arch wall 108 has a passage 121 which is directly above the grate100 and communicates with the fire box. 110 and superheater chamber 117.damper 122 is 10- catcd within the supcrhcatcr chamber 117 and isdesigned to slide upon the upper surface of the arch wall 108 toregulate the amount of opening of the passage 121 into the superheaterchamber. This damper 122 is connected with a rod 123. said rod extendingthrough the front wall of the boiler casing and is pro ided with ahandle 125 to facilitate the longitudinal movement thereof.

With this construction, the baffle wall 114 and arch gwall 108 cause aportion of the products of combustion to pass directly between the tubes112, and another orti'on of the products of combustion pass irectlythrough the passage 121 into the combustion chamber to heat thesuperheater 118. Therefore, using my invention in connection with aboiler of thistype, I am able to secure superheated steam at anextremely high temperature.

In Fig. 5, I have shown my improved superheating construction inconnection with what is known as a Sterling boiler.

In this form of boiler, I produce the superheating 'chamber insubstantially the same manner as described in connection with myimproved boiler shown in Fig. 1. That is, I provide an arch wall 126,which extends rearwardly of the front wall 127 of the boiler casing to aposition adjacent the forward tubes 128 of the boiler unit- 129. Fromthis arch wall can be erected a bafile wall 130 which leads upwardlyinto close proximity to said tubes 128. I thus provide a superheaterchamber 131 into which projects a superheater 132.

The arch wall 126 has a passage 133 which is directly above the grate134 and fire box 114 as shown in the upper surface of the arch wall 126and this damper can be actuated by means of a rod 137 which extendsthrough the upward wall of the boiler casing, so that said damper may bemoved over the passage 133 to vary the amount of opening of said passageinto the superheater chamber 131.

In the construction illustrated, it will be noted that a portion of theproducts of combustion will pass upwardly from the grate 134 and firebox 135 through the passage 133 into the superheater chamber 131, sothat the steam within the superheater will be heated to an extremelyhigh temperature.

The other portion of the products of combustion will be forced to passbetween the inner end 138 of the arch wall 126 and the tubes 128 of theboiler unit 129 to effectively heat the latter. 1

In the form of my invention shown in Fig. 6, instead of providing thebattle wall Fig. 4, I provide a baffle 139 which is made of fire bricktiles 140 and rests upon the lower tubes 112.

It will be noted that in each of the forms illustrated, the extremelyhot products of combustion will pass directly from the grate and firebox through the passage in the arch wall into the superheater chamberprior to the engagement of said products with any other body. Theintensity of this heat within the superheater chamber can be regulatedby the movement of the damper so that it is possible with my inventionto control the temperature of the superheated steam which is of materialadvantage in view of the numerous requirements and demands forsuperheated steam.

While I have described my invention as taking a particular form, it willbe understood that the various parts of my invention may be changedwithout departing from the spirit thereof, and hence I do not limitmyself to the precise construction set forth, but consider that I am atliberty to make such changes and alterations as fairly come within thescope of the appended claims.

' water tubes,

above the fire box and communicating with the latter and the superheaterchamber, substantially as described.

2. The combination with a boiler casing,

angularly disposed of a boiler unit having providing a fire box, anabove said fire box, a bafiie wall leading directly to said tubes at itsupper end and joining the arch wall at its lower end to provide achamber, a superheater extending into said chamber, said arch wallhaving a passage directly above the fire box and communicating with thelatter and the superheater chamber, and a damper operative to regulatethe size of said passage, substantially as described.

a 3. The combination with a boiler casing, of means providing a firebox, a water tube boiler unit adjacent the fire box, an arch walldirectly above the fire box and having a portion extending into closeproximity with the tubes of the boiler unit, a bafiie wall projectingupwardly from wall and having a portion located adjacent the tubes ofsaid boiler unit, said arch wall and baffle Wall providing a chamberwithin said casing, a superheater extending into said chamber, a bafllelocated adjacent to certain of the tubes of said boiler unit watertubes, means arch wall directly which are remote from said arch wall toprovide a passa e between the arch wall and said latter bafi e said archwall having a passage communicating with the fire box and thesuperheater chamber, and a damper operative to regulate the amount ofopenlng of said passage into the superheater chamber, substantially asdescribed.

4. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit adjacent the fire box, an arch wall directlywith the tubes of the boiler unit, a. b a wall projecting upwardly fromthe arch wall and havlng a portion located adjacent the tubes of saidboiler unit, said arch wall and baflie wall said casing, a said chamber,certain of the tubes sulperheater extending into a afile locatedadjacent to passage between the arch wall and said latter bafiie, saidarch wall having a passage communicating with the fire box and thesuperheater chamber, said battle wall providing an outlet passage forthe products of combustion assing through the superheater chamber, sustantially as described.

5. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit ad'acent the fire box, an arch wall directly ave the fire box and having a portion extending into close proximity withthe tubes of the boiler unit, a, bafile wall rojecting upwardly from thearch walland having a portion located adjacent the tubes of said boilerunit, said arch wall and baths wall providing a chamber within saidcasing, a superheater extending into said chamher, a bafiie locatedadjacent to certain of above the fire box and having: a portionextending into close proximit of said boiler unit which are remote fromsaid arch wall to provide a the arch providing a chamber within .sagebetween the arch wall and said latter battle, said arch wall having apassage communicating with the fire box and the super heater chamber,said battle wall providing an outlet passage for the products ofcombustion passing through the superheater chamber, said outlet passagecommunicating with the first-mentioned passage, substantially asdescribed.

6. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit adjacent the fire box, an arch Wall directlyabove the fire box and having 'a portion extending into close proximitywith the tubes of the boiler unit, a bafiie wall projecting upwardlyfrom the arch wall and having a portion located adjacent the tubes ofsaid boiler unit, said arch wall andibafiie wall providing a chamberwithin said casing, a superheater extending into said chamber, a bafilelocated adjacent-to certain of the tubes of said boiler unit which areremote from said arch wall to provide a passage between the arch walland said latter baffle, said arch wall having a passagecommunicating-with the fire box and the superheater chamber, said bafHewall providing an outlet passage for the products of combustion passingthrough the superheater chamber, said outlet passage communicating withthe first-mentioned passage, and a damper operative to regulate theamount ofopening of said second-mentioned passage into the superheaterchamber, substantial y as described.

7. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit adjacent the fire box, an arch wall directlyabove the fire box and having a portion extending into close proximitywith the tubes of the boiler unit, a battle wall projecting upwardlyfrom the arch wall and having a portion located adjacent the tubes ofsaid boiler unit, said arch wall and baflle wall providing a chamberWithin said casing, a superheater extending into said chamber, a bafilelocated adjacent to certain of the tubes of said boiler unit which areremote from said arch wall to provide a passage between the arch walland said latter bafiie, said arch wall having a passage communicatingwith the fire box and the superheater chamber, said baffle wallproviding an outlet passage for the products of combustion passingthrough the superheater chamber, said outlet passage communicating withthe first-mentioned passage, and a damper operative to regulate theamount of opening of said second-mentioned passage into the superheaterchamber, said battle providing a passage between the tubes of the boilerunit, said passage communicating Wltll the outlet passage of thesuperheater chamber and with said first-mentioned pas sage,substantially as described.

8. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit adjacent the fire box, and including upper andlower drums connected by tubes, a battle located between the tubes andextending upwardly from the lower drum, said battle stopping short ofthe upper drum to provide a passage, an arch wall directly above thefire box and having a portion extending into close proximity with theouter tubes of the boiler unit, a baifie wall projecting upwardly fromthe arch wall and having a portion located adjacent said outer tubes,said arch wall and baflie wall providing a chamber within said casing, asuperheater extending into said chamber, said arch wall having a passagecommunicating with the fire box and the superheater chamber,substantially as described.

9. The combination with a boiler casing, of means providing a fire box,a Water tube boiler unit adjacent the fire box, and includlng upper andlower drums connected by tubes, a battle located between the tubes andextending upwardly from the lower drum, said baflle stopping short ofthe upper drum to provide a passage, an arch wall directly above thefire box and having a portion extending into close proximity with theouter tubes of the boiler unit, a baflle wall projecting upwardly fromthe arch wall and having a portion located adjacent said outer viding achamber within said casing, a superheater extending into said chamber,said arch wall having a passage communicating with the fire box and thesuperheater chamber, and adamper operative to regulate the amount ofopening of said latter passage into the superheater chamber,substantially as described.

10. The combination with a boiler casing, of means providing a fire box,a water tube boiler unit adjacent the fire box, and includmg upper andlower drums connected by tubes, a battle located between the tubes andextending upwardly from the lower drum, said bafile stopping short ofthe upper drum to provide a passage, an arch wall directly above thefire box and having a portion extending into close proximity with theouter tubes of the boiler unit, a baflie wall projecting upwardly fromthe arch wall and having a portion located adjacent said outer tubes,said arch wall and bafile wall providing a chamber within said casing, asuperheater extending into said chamber, said arch wall having a passagecommunicating with the fire box and the superheater chamber, said bafflewall terminating at its top below the upper drum of the boiler unit toprovide an outlet passage for the superheater chamber whereby the outletpassage communicates with said first-mentioned passage to permit theproducts of combustion passing upwardly through the superheater chamberto combine with the portion of said products which pass between the archwall and the baffle prior to passing through said firstmentionedpassage, substantially as de scribed.

11. The combination with a boiler casing,

of means providing a fire box, a water tube boiler unit adjacent thefire box, and including upper and lower drums connected by tubes, abaffle located between the tubes and extending upwardly from the lowerdrum, said bafile stopping short of the upper drum to provide a passage,an arch wall directly above the fire box and having a portion ex tendinginto close proximity with the outer tubes of the boiler unit, a baflleWall projecting upwardly from the arch wall and having a portion locatedadjacent said outer tubes, said arch wall and baflle wall providing achamber within said casing, a superheater extending into said chamber,said arch wall having a passage communicating with the fire box and thesuperheater cham her, said bafile wall terminating at its top below theupper drum of the boiler unit to provide an outlet passage for thesuperheater chamber whereby the outlet passage communicates with saidfirstmentioned passage to permit the products of com-- bustlon passingupwardly through the superheater chamber to ,combine with the portion ofsaid products which pass between the arch Wall and the baflle prior topassing through said first-mentioned passage, and a damper operative toregulate the amount of opening of the passage which leads from the firebox to the superheater chamber, substantially as described.

11 testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

EDWARD O. MEIER. Witnesses: y

N. JOHN NELsoN, EUGENE V. HEII'JMAN.

